Introduction: The Making of a Powerful Low Cost Coilgun Which Is Portable

By None
About: Technician by proffession.

In this intructable i will show you how i made my coilgun, I will first thank, steaveastrouk, re-design, lemonie, orksecurity and others who helped me with my questions.  I became quite interested with this coilguns from the videos that was featured on hacked gadgets and intructable. So i decided to make my own research to understand how it works. After months of research i decided to go to the practice session.



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Step 1: Parts List

Well for the design use you imagination because the parts that i used for the casing will be very difficult to find because they are all from a dismantled photocopier. Therefore for the electronics you will need some parts that is easily available on market or by salvaging them

Parts

  400V Electrolytic Capacitors. The more capacitance the better it will be. say like over 2000uf or more (Free)
 1k 10W resistors X 2(Rs20)
 BD243C or 2N6121 transistor or equivalent X2(Rs64)
 A centre tapped transformer on primary. we will come to that later on(free)
 A power supply that is rectified mains, car battery, or other batteries, in my case i used 10 AA 1.2V NI-CD batteries (12v in series)  (free)
 Some very very high current switches or relays(free)
 Full Bridge Rectifier 400V 3A or more to be on the safe side X 2 (free, salvaged from TVs)
 A 100W bulb(Rs21)
 Lots of wires(Free)
 Aluminium Tubing(R75)
 Enamel coated wire, i used the 1.2mm wire that i got from a tv.(free),, u can also use bigger wire for more current
2 Medium Heat sinks

Step 2: Tools and Other Materials You Will Need

Tools
Hot melt glue gun
Soldering iron
Grinder
Jigsaw
Wire cutter and wire stripper
Pencil for marking...............
Drilling machine

 Useful goodies
.
Metal sheefs and a food container(plastic) of appropriate size for the casing and  insulation
Duct tape or electrical tape
Solder the 2mm one
Flux (optional if your solder is not of too good quality)
Wood 
Card Board
Battery holder

  Probably most important is a place to work. i conquered my mother's kitchen a few years ago and made it my workshop

Step 3: The Capacitor Bank

Find the maximum number of 400v electrolytic capacitors and connect them in parallel.

My capacitor bank ended up having a capacitance of 3475uF

 If you have 200v ones. connect them in series to give 400v and then in parallel to increase capacitance. 
Make sure you use very thick wires because it will be driving current up to 350A.
Beware of polarities, it can result in a big capacitor explosion

you can probably use different capacitor values, but it would mess with the pulse time and it would not work nearly as well as it would if you used, say, all 120 uF 330V capacitors. The different uF values mean that each capacitor will have a different discharge pulse time, so if you graphed the charge put out over time the line would be all squiggly and not like the ideal curve that a uniform bank would have. In a worst case scenario the coilgiun might end up shooting the projectile backward, but I don't think that that could actually happen. It probably will just shoot it really slow.

therefore i recommend you to use close values of capacitance of each capacitor. Mine is really messed up, but i am fairly satisfied with it's performance

Step 4: Making Your Coil

Well not much to say, Google is here

I used 2 wires for one coil to decrease the resistance.

 i attached a tube to my drill and started winding the coil

 Here are the two coils I've made

 Note that if you use high voltage of about 1KV or more you can use thinner wires with more turn,
if you use low voltage, thicker wire will be needed,

I= V/R

Step 5: Getting Started With the Capacitor Charger

I've seen a lot of people using disposable cameras capacitor charger for their gun. The disadvantages of it are

1. Takes about 5min to charge a big capacitor bank due to its small size, it won't carry current needed for good charging time
2. Combining chargers are good but will not last long and the cameras here in Mauritius are difficult to find
3. Disposable camera means one time use, therefore it will work for a limited amount of time

 I designed my own charger using combining mains supply and battery supply.

  feel free to modify the schematic if you want. It is a simple push pull driver.   

Charging time with my charger
3s from mains section
7s from battery secton
1s with 2 methods combined

Step 6: Packing Em in One

connect everything according to schematic below and you are done.

Relays allow more current to pass through them than regular push button switches, which normally weld together and then gets damaged.YOU can replace the relay with other devices like a thyristor or a big momentary switch.I found it best to use a relay because it switches very quickly and therefore last longer than other normal switches. most of the time the switches are damaged at the internal contact leads. 




i leave the casing development on you because parts are too uneven to find or make as is

 I will put other videos of it later on.

Total cost of Project: RS200(about $7)

Future developments
1. Make it more powerful using more capacitors,
2. Using a more efficient coil.
3. Try to use my 600A 1200V thyristor( this is so heavy
3. Reduce the charging time from mains to 1s
6. Place a laser pointer.
7. Design a semi automatic reload system.(  just like the one that was featured on hacked-gadgets



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